Fuel compositions for vehicles are continually being improved to enhance various properties of the fuels in order to accommodate their use in newer, more advanced engines. Accordingly, the fuel compositions contain additives which are directed to certain properties that require improvement. For example, friction modifiers, such as fatty acid amides, are added to fuel to reduce friction and wear in the fuel delivery systems of an engine. Other additives are included in the fuel compositions to reduce the corrosion potential of the fuel composition and/or improve the conductivity property of the fuel composition. Still other additives are added to the fuel to improve the fuel economy of an engine operating on the fuel. Each of the foregoing additives may be effective to improve a single property of the fuel composition and, in some instances, may adversely affect other properties of the fuel composition. Accordingly, fuel compositions typically include a complex mixture of additives that are selected to cooperate with each other to improve the fuel composition. Some of the additives may be beneficial for one characteristic, but detrimental to another characteristic of the fuel. Accordingly, there is a need for a fuel additive that is effective to improve multiple characteristics of a fuel.
Engine and fuel delivery system deposit is a particularly important problem for modern combustion engines and deposit control additives are used to mitigate this problem. For example, diesel engines suffer deposit in the fuel delivery system. Well known succinimide type detergents offer limited detergency as measured by industry DW10 and XUD9 tests.
Gasoline engines also suffer deposit problems. Commonly known type detergent such as Mannich detergent did not provide sufficient cleaning power.
Quaternary ammonium compounds such as alkoxylated salts have recently been developed as very effective detergents compared to conventional succinimide and Mannich base detergents. Quaternary ammonium compounds are known as is disclosed in U.S. Pat. No. 8,147,569. However highly dangerous ethylene oxides and propylene oxides are required to make such detergents.
Quaternary ammonium compounds through alkylation with dialkyl carbonate are also disclosed in U.S. Pat. No. 8,147,569. However the carbonate anion part of the molecule is susceptible to precipitation and drop out in fuels or additive packages. In addition, the detergency of quaternary ammonium carbonates may still need to be improved.
In accordance with the disclosure, exemplary embodiments provide a fuel additive composition, fuel composition, method of improving the injector performance of a fuel injected engine, method of reducing wear in a fuel system of an engine, and method of improving the demulsibility of a fuel composition. The fuel composition includes from about 5 to about 300 ppm by weight based on a total weight of the fuel composition of a hydrocarbyl soluble quaternary ammonium carboxylate derived from a quaternary ammonium carbonate and an organic acid.
One embodiment of the disclosure provides a method of improving the injector performance of a fuel injected engine. The method includes combusting in the engine a fuel composition comprising a major amount of fuel and from about 5 to about 300 ppm by weight based on a total weight of the fuel composition of a hydrocarbyl soluble quaternary ammonium carboxylate derived from a quaternary ammonium carbonate and an organic acid.
Another embodiment of the disclosure provides a method of reducing wear in a fuel system of an engine. The method includes operating the engine on a fuel composition comprising a major amount of fuel and from about 5 to about 300 ppm by weight based on a total weight of the fuel composition of a hydrocarbyl soluble quaternary ammonium carboxylate derived from a quaternary ammonium carbonate and an organic acid.
A further embodiment of the disclosure provides a method of improving the demulsibility of a fuel composition. The method includes providing as a fuel composition a major amount of fuel and from about 5 to about 300 ppm by weight based on a total weight of the fuel composition of a hydrocarbyl soluble quaternary ammonium carboxylate derived from a quaternary ammonium carbonate and an organic acid.
Another embodiment of the disclosure provides a process of making a hydrocarbyl substituted amido-trialkyl quaternary ammonium carbonate. The process includes reacting an amidodialkylamine with dialkylcarbonate in the mole ratio of amine to carbonate of from about 1:1 to about 1:1.5 at a temperature ranging from about 120° to about 160° C. in a reaction medium substantially devoid of a protic solvent.
Additives of the disclosure may overcome the deficiencies of current known fuel detergents by providing improved detergency and reduced negative impact on fuel demulsibility. In addition, the additive may also be capable of reducing engine wear using both petroleum and ethanol containing gasoline fuels.
An advantage of the compositions and methods described herein is that the additive composition and the fuel composition may not only improve the friction and wear properties of the fuel, but the additive composition may be effective to improve fuel economy, and/or to clean up or prevent deposits on engine parts and in fuel systems for engines at relatively low treat rates.
Another advantage of the fuel additive described herein is that the additive composition may be used at a relatively low concentration in combination with conventional fuel additives to provide enhanced engine performance.